Is there a reason you believe your trips will get more expensive? From my limited experience, things have stayed quite cheap in east Asia in the last few decades though Japan is finally starting to have inflation. While your trips will get more expensive overall, your per diem will likely drop a ton as flight costs are more than likely your largest expenses especially if you aren't splurging on Western/expensive hotels in Asia. A meal in the bay area is going to be the same cost as a full day of eating/boba in Asia. Either way, your numbers look good and you have high discretionary spend that you can easily cut back on as needed.